Wireless precision piezoelectric thermometer using an RF excitation-detection technique with an NMR probe

Based on an inductive RF excitation-detection scheme, a quartz-crystal temperature-measuring device is described for applications in MRI and MRS scanners where strong electric and magnetic fields are present. A quartz-crystal resonator with a high temperature sensitivity (88 ppm/degrees C) is employed as the temperature sensor. Changes in the quartz resonance frequency reflecting temperature variations are detected by a NMR coil multiply tuned to the resonance frequencies of the quartz crystal and the nuclei of interest. This wireless probe is simple to build and is capable of measuring temperature changes from -50 to +150 degrees C. The high frequency linearity of the device in this temperature region ensures a simple calibration procedure and a constant temperature resolution.